A prospective trial of prenatal screening for Down syndrome by means of maternal serum alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol.
A prospective trial of prenatal screening for Down syndrome by means of maternal serum alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol. Am J Obstet Gynecol. 1993 Sep; 169(3):526-30.